LabelRenderer.java

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// LabelRenderer.java

package renderkits.renderkit.xul;

import javax.faces.component.NamingContainer;
import javax.faces.component.UIComponent;
import javax.faces.component.UINamingContainer;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;

import java.io.IOException;
import java.util.logging.Level;

/** <p><B>LabelRenderer</B> renders Label element.<p>. */
public class LabelRenderer extends BaseRenderer {

    //
    // Protected Constants
    //
    //
    // Class Variables
    //

    //
    // Instance Variables
    //
    private static final String RENDER_END_ELEMENT =
          "com.sun.faces.RENDER_END_ELEMENT";
    // Attribute Instance Variables

    // Relationship Instance Variables

    //
    // Constructors and Initializers    
    //

    public LabelRenderer() {
        super();
    }

    //
    // Class methods
    //

    //
    // General Methods
    //

    //
    // Methods From Renderer
    //

    public void encodeBegin(FacesContext context, UIComponent component)
          throws IOException {

        if (context == null || component == null) {
            // PENDING - i18n
            throw new NullPointerException("'context' and/or 'component is null");
        }

        if (logger.isLoggable(Level.FINER)) {
            logger.log(Level.FINER,
                       "Begin decoding component " + component.getId());
        }
        ResponseWriter writer = null;
        String forValue = null;
        String styleClass = (String)
              component.getAttributes().get("styleClass");

        // suppress rendering if "rendered" property on the component is
        // false.
        if (!component.isRendered()) {
            if (logger.isLoggable(Level.FINE)) {
                logger.fine("End encoding component " +
                            component.getId() + " since " +
                            "rendered attribute is set to false ");
            }
            return;
        }
        writer = context.getResponseWriter();

        UIComponent forComponent = null;
        String forClientId = null;
        forValue = (String) component.getAttributes().get("for");
        if (forValue != null) {
            forComponent = getForComponent(context, forValue, component);
            if (forComponent == null) {
                // it could that the component hasn't been created yet. So
                // construct the clientId for component.
                forClientId = getForComponentClientId(component, context,
                                                      forValue);
            } else {
                forClientId = forComponent.getClientId(context);
            }
        }

        // set a temporary attribute on the component to indicate that
        // label end element needs to be rendered.
        component.getAttributes().put(RENDER_END_ELEMENT, "yes");
        writer.writeText("\n", null);
        writer.startElement("box", component);
        String boxClass = (String)
              component.getAttributes().get("boxClass");
        if (boxClass != null) {
            writer.writeAttribute("class", boxClass, "boxClass");
        }
        String boxStyle = (String)
              component.getAttributes().get("boxStyle");
        if (boxStyle != null) {
            writer.writeAttribute("style", boxStyle, "boxStyle");
        }
        String pack = (String)
              component.getAttributes().get("pack");
        if (pack != null) {
            writer.writeAttribute("pack", pack, "pack");
        }
        writer.writeText("\n", null);
        writer.startElement("label", component);
        writeIdAttributeIfNecessary(context, writer, component);
        if (forClientId != null) {
            writer.writeAttribute("control", forClientId, "control");
        }

        String style = (String)
              component.getAttributes().get("style");
        if (null != style) {
            writer.writeAttribute("style", style, "style");
        }
        if (null != styleClass) {
            writer.writeAttribute("class", styleClass, "styleClass");
        }

        // render the curentValue as label text if specified.
        String value = getCurrentValue(context, component);
        if (logger.isLoggable(Level.FINE)) {
            logger.fine("Value to be rendered " + value);
        }
        if (value != null && value.length() != 0) {
            boolean escape = true;
            Object val = null;
            if (null != (val = component.getAttributes().get("escape"))) {
                if (val instanceof Boolean) {
                    escape = ((Boolean) val).booleanValue();
                } else if (val instanceof String) {
                    try {
                        escape =
                              Boolean.valueOf((String) val).booleanValue();
                    } catch (Throwable e) {
                    }
                }
            }
            writer.writeAttribute("value", value, "value");
        }
        writer.flush();
    }


    public void encodeEnd(FacesContext context, UIComponent component)
          throws IOException {

        if (context == null || component == null) {
            // PENDING - i18n
            throw new NullPointerException("'context' and/or 'component is null");
        }

        // render label end element if RENDER_END_ELEMENT is set.
        String render = (String) component.getAttributes().get(
              RENDER_END_ELEMENT);
        if ("yes".equals(render)) {
            component.getAttributes().remove(RENDER_END_ELEMENT);
            ResponseWriter writer = context.getResponseWriter();
            writer.endElement("label");
            writer.writeText("\n", null);
            writer.endElement("box");
        }
        if (logger.isLoggable(Level.FINER)) {
            logger.log(Level.FINER,
                       "End encoding component " + component.getId());
        }
    }

    /**
     * Builds and returns the clientId of the component that is
     * represented by the forValue. Since the component has not been created
     * yet, invoking <code>getClientId(context)</code> is not possible.
     *
     * @param component UIComponent that represents the label
     * @param context   FacesContext for this request
     * @param forValue  String representing the "id" of the component
     *                  that this label represents.
     *
     * @return String clientId of the component represented by the forValue.
     */
    private String getForComponentClientId(UIComponent component,
                                           FacesContext context,
                                           String forValue) {
        String result = null;
        // ASSUMPTION: The component for which this acts as the label
        // as well ths label component are part of the same form.
        // locate the nearest NamingContainer and get its clientId.
        UIComponent parent = component.getParent();
        while (parent != null) {
            if (parent instanceof NamingContainer) {
                break;
            }
            parent = parent.getParent();
        }
        if (parent == null) {
            if (logger.isLoggable(Level.WARNING)) {
                logger.warning("component " + component.getId() +
                               " must be enclosed inside a form ");
            }
            return result;
        }
        String parentClientId = parent.getClientId(context);
        // prepend the clientId of the nearest container to the forValue.
        result = parentClientId + UINamingContainer.getSeparatorChar(context) + forValue;
        return result;
    }

    /**
     * Locates the component identified by <code>forComponent</code>
     *
     * @param forComponent - the component to search for
     * @param component    - the starting point in which to begin the search
     *
     * @return the component with the the <code>id</code that matches
     *         <code>forComponent</code> otheriwse null if no match is found.
     */
    private UIComponent getForComponent(FacesContext context,
                                        String forComponent,
                                        UIComponent component) {
        if (null == forComponent || forComponent.length() == 0) {
            return null;
        }

        UIComponent result = null;
        UIComponent currentParent = component;
        try {
            // Check the naming container of the current
            // component for component identified by
            // 'forComponent'
            while (currentParent != null) {
                // If the current component is a NamingContainer,
                // see if it contains what we're looking for.
                result = currentParent.findComponent(forComponent);
                if (result != null) {
                    break;
                }
                // if not, start checking further up in the view
                currentParent = currentParent.getParent();
            }
            // no hit from above, scan for a NamingContainer
            // that contains the component we're looking for from the root.
            if (result == null) {
                result =
                      findUIComponentBelow(context.getViewRoot(), forComponent);
            }
        } catch (Throwable t) {
            //PENDING i18n
            throw new RuntimeException("Component not found:" + forComponent);
        }
        // log a message if we were unable to find the specified
        // component (probably a misconfigured 'for' attribute
        if (result == null) {
            if (logger.isLoggable(Level.WARNING)) {
                //PENDING i18n
                logger.warning("Component not found in view:" + forComponent);
            }
        }
        return result;
    }

    // The testcase for this class is TestRenderResponsePhase.java

} // end of class LabelRenderer